Below is a (silent) screen recording of adding the viewbook embed code to your site. Sorry, there is no microphone on my computer.
The proper embed code is the following:
<iframe style="width:900px;height:500px" src="https://online.fliphtml5.com/rjpnm/nzpg/" seamless="seamless" scrolling="no" frameborder="0" allowtransparency="true" allowfullscreen="true" ></iframe>